Mathematical drawing instrument.



V. M SP'UNAR. MATHEMATIOALDRAWING INSTRUMENT.

APPLICATION FILED J'AlLZl, 1908.

PatentedApr. 12, 1910.

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V. M. SPUN AR. I MATHBMATIGAL DRAWING INSTRUMENT.

APPLICATION I'ILHI) JAN. 21, 1908.

Patented Apr.-12,- 1910.

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UNITED STATES PATENT OFFICE.

VALENTINE MAR. SPUNAR, OF EAST PITTSBURG, PENNSYLVANIA.

MATHEMATICAL DRAVJING INSTRUMENT.

Application filed January 21, 189.8.

To all whom it may concern:

Be it known that I, VALENTINE MAR. SPUNAR, a subject of Austria-Hungary,residin at East Pittsburg, in the county of Allegheny and State ofPennsylvania, have invented certain new and useful Improvements inMathematical Drawing Instruments; and I do declare the following to be afull, clear, and exact description of the invention, such as will enableothers skilled in the art to which it appertains to make and use thesame, reference being had to the accompanying drawings, and to thecharacters of reference marked thereon, which form a part of thisspecification.

My invention relates to certain new and useful improvements in drawinginstruments designed principally for use in forming mathematicallycorrect design work, such as ellipses, fluted configurations etc.

The primary object of my invention is to provide an instrument of thecharacter described that will be of great service in drafting rooms andalso for designing purposes, in fact it will be of a general utility forall classes of drawing.

In the accompanying drawings, in two sheets, Figure 1 is a side view inelevation of the instrument in assembled form. Fig. 2 is a top plan viewof the same. Fig. 8, Sheet 2, is a cross sectional view showing detailconstruction of the supporting column which constitutes the pivotalpoint of the instrument. Fig. 4 is a diagrammatical view of the arc oftravel taken by the different parts in the formation of an ellipse. Fig.5 shows another design that can be made with my device.

Throughout the different views shown in the drawings the numeral 1designates the frame work constituting the supporting column and pivotalpoint of my device. As will be seen by reference to Fig. 3, this column1 has a comparatively broad base in order to afford a steadying meanswhile the device is being operated, at each side of which are providednon-friction bearings 22. In the center of this column is arranged anadjustable pin 3, which serves as a pivotal point when the instrument isin service. This pin is held securely in position by means of a setscrew 4. To the upper portion of this column 1 is secured a supportingbar 5, which extends outward at right angles to said column and may beof any desired length and provided on its face with Specification ofLetters Patent.

1 a scale, not shown. 1 umn 1s provided a knob or contact piece (3Patented Apr. 12, 191i).

Serial No. 412,916.

011 the top of said colwhich serves as a turning means for oper atingthe device. Operatively extending through the supporting column 1, at apre determined point, but preferably at about midway of its height is asleeve 7, the inner end being provided with a limiting collar 8. Theopposite end of this sleeve is provided with a split tapered andthreaded portion 9 upon which end is mounted a screw collar 10. Mountedover this sleeve and adjustable thereon is a wheel 11 having a sharpmilled contacting edge 12 designed to travel on the drawing board. Thiswheel is formed with a tapering portion having sufiicient materialtherein to causesaid wheel to keep a close contact with the drawingboard during the operation of the device. This wheel is also providedwith split tapered and threaded port-ion 13, upon which is mounted ascrew collar 14.

Suspended from, and operatively attached to, the supporting bar 5, bymeans of a slotted guide portion 5, or any other suitable manner, is ahousing member 15 which is secured in position, when properly adjusted,by means of a set screw 16.

Extending through the sleeve 7 is a shaft 17, the inner end beingoperatively connected with the housing 15 and having mounted thereon abeveled gear 18. The gear meshes in a similar gear 19, their relation,with reference to teeth, being preferably one to one. This lattermentioned gear is mounted on a radial supporting member 20 which may beconstructed in the form shown-or it may be made in any other desiredshape. Through this said member 2 passes an adjustable radial bar member21, held in position by a set screw 20, on one end thereof beingprovided a holder 22 for receiving a marking pen or pencil 23. hismarking member is kept in close engage ment with the drawing board bymeans of a small tension spring 24 which bears against a collar 25provided on the said marker. This latter feature is not necessarilymaterial to the proper working of my device as any other suitable meansfor keeping the marker in contact with the paper, may be substituted.

In order to form an ellipse with my drawing instrument illustrated bythe dia grammatical view Fig. 4 the wheel 11 is first positioned andsecurely held by means of the screw collar 14 on the sleeve 7 at a pointwhere the milled traveling edge 12 will be exactly two inches from thefixed or pivotal point 3. lVhen the instrument is turned or operated bymeans of the knob 6, the wheel 11 will describe a perfect circle aroundthe fixed pivot A and when the wheel 11 is made to travel from the pointC to the point D the shaft 17 will be caused to turn, owing to it beingheld to the sleeve 7 by means of the screw collar 10, thus revolving the18 meshing with the gear 19, thereby turning the member 20 and carryingthe radial bar 21, supporting the marking member 23, so that said markerwill travel in path B to E; which will complete one quarter of theellipse.

The radius of the wheel 11 to the distance between the plane of its edge12 and the pivotal point 3, determines the number of revolutions made bythe meshing gears 18 and 19, and consequently the movement of the radialmember 20. lVhen the traveling edge 12 of said wheel 11 positioned attwo inches from the pivot 2) the ratio will be as one to two, onerevolution of said wheel causing the gears to rotate twice, therebydrawing the marking member in its arc of travel, which, when completed,forms a perfect ellipse of pie-determined length and width. The nearersaid traveling edge 12 is brought to the pivotal point 3 the less theratio, and the farther away the greater the ratio.

The length of the bar 21, or in other words the radius of the markingpoint 23 away from the pivotal point 20, determines the are of travel ofsaid marker. The nearer said imn'ker is placed to the pivotal point 20the shorter the radius and the closer it will describe a circle, and thefarther away it is placed the longer the radius and the more pronouncedwill become the ellipse. The path of the pivotal point 20, while makingthe segmental ellipse shown, is marked by dotted lines from F to G. Thedistance of the traveling edge 12, of the wheel 11, away from thepivotal point 3 determines the clmracter of the design and the distanceof the marking point 23 away from the pivotal point 20, and likewise thedistance the housing member 15 is placed away from the said point 3,determines the curvature of the design.

The normal relation of the distance be tween the pivotal point 3 and thetraveling edge 12, to the longest radius of the wheel 11, being as oneto two for forming an ellipse, when this relation is changed, byincreasing or diminishing the distance of the said traveling edge awayfrom said pivotal point 3 thereby causing said wheel to describe a wideror smaller circle, the consequent result is, that the revolution of saidmeshing gear will be relatively increased or reduced according to thedistance traveled by said wheel 11, which will cause the member 20 toturn in unison, thereby drawing the marking point 23 in a path, otherthan an ellipse; the design shown in Fi 5 being an example.

In order to adjust the housing member 15, on the supporting bar 5, theset screw 16 is first turned away from contact with said supporting barand the screw collar 10 turned off the taper screw 9, which will thenpermit of the shaft 17 being moved through the sleeve 7.

Having described and shown my invention what I claim and desire tosecure by Letters Patent is:

1. In a drawing instrument, a suitable supporting frame work providedwith a pivotal point; a bar member extending outward at right angleswith the said supporting frame; a housing operatively mounted on saidbar; a sleeve operatively seated through the supporting frame work; awheel mounted on said sleeve; a shaft extending through said sleeve, oneend engaging in the housing; a radial member operatively seated in, andcarried by, said housing; meshing gears mounted on the radial member andshaft; and an adjustable rod carried by the radial member, on one endbeingmounted a suitable holder for a marker.

2. In a drawing instrument, a suitable supporting frame work providedwith a pivotal point; a bar member extending outward at right angleswith the said supporting frame; a housing operatively mounted on saidbar; a sleeve operatively seated through the supporting frame work,having a limiting means at one end thereof; a wheel mounted 011 saidsleeve, said wheel being provided with a sharp traveling edge, also asecuring means; a shaft extending through said sleeve, one end engagingin the housing; means for clamping or holding the sleeve to the shaft; aradial member operatively seated in, and carried by, said housing;meshing gears mounted on the radial member and shaft; and an adjustablerod carried by the radial member, on one end being mounted a suitableholder for a marker.

In testimony whereof, I afiix my signature, in presence of twowitnesses.

VALENTINE MAR. SPUNAR.

Witnesses:

BEATRICE FITZGERALD, H. W. STEVENSON.

